The area will feature "soft ambient" lighting, and kids under the
age of 12 are not allowed.

Air Asia X says Quiet Zone seating is available for no extra
charge, but interested travelers will have to pay the fee for
selecting their seats ($11 in economy, $35.50 in the "hot seat"
section, with more leg room).

The extra distance may not do much to dampen the sounds of a
screaming baby, but at least Quiet Zone travelers won't have to
deal with any toddlers kicking their seats.